A laryngoscope is described and shown for use in opening an airway for orotracheal intubation and, more particularly, a laryngoscope for simultaneously displacing the tongue muscle for exposing the glottis for intubating a patient with an endotracheal tube.
Oral or nasal endotracheal intubation procedures are commonly employed to secure a controlled airway and to deliver inhalant oxygen, anesthetic gases, and other therapeutic agents into the trachea and lungs of human and veterinary patients. Laryngeal exposure to visualize vocal cords and facilitate airway control through intubation is a key element in anesthesia and emergency medicine rapid sequence intubation. A laryngoscope is a key instrument for intubation procedures.
A conventional laryngoscope typically includes a handle and a blade. A proximal end of the blade is detachably connected to a distal end of the handle such that the blade extends generally normally forwardly from the handle in an L-shaped configuration. Many types of laryngoscope blades have been developed, each characterized by blade curvature, the point of such curvature, and the flange structure of the blade. The primary function of the laryngoscope in orotracheal intubation is to open the mouth and expose the larynx in order to facilitate the insertion of the endotracheal tube into the trachea. The laryngoscope blade serves to displace the tongue and allow direct visualization of the vocal cords through the mouth.
During intubation, a patient is often paralyzed with paralytic drugs or unconscious and not spontaneously breathing. With seconds or minutes to secure an airway, the patient is placed in a supine position with the head tilted backwardly. The laryngoscope blade is usually inserted laterally from the right side of the mouth in order to sweep the tongue mass to the left. The blade is directed medially or rotated slightly counter-clockwise to engage, lift and sweep the tongue away from the lumen of the pharyngeal outlet for adequate visualization of the vocal cords. The laryngoscope may be further manipulated to expose the glottic opening. In its final position, the rigid blade tip ends up angled to the left within the vallecula. The endotracheal tube is then introduced through the mouth and visually advanced, passing between the vocal cords into the subglottic space for securing the airway. Once placement of the endotracheal tube has been achieved, the laryngoscope blade is removed.
Intubation procedures involving laryngoscopy require training, skill and strength. Much of the effort goes to moving the large mass of the tongue to expose the airway and visualize the vocal cords. Unfortunately, only a small portion of the surface of the conventional blade can be used efficiently to move the tongue. In the final position, only a small portion of the blade tip engages the base of the tongue tissue, which is not effective.
Moreover, during insertion of the laryngoscope, care must be taken to avoid pressure on the teeth and gums of the patient and avoid traumatizing both the oral mucosa and the epiglottis. The process of laryngoscopy forces, at times, the users to use a levering action with the fulcrum about the teeth. This much needed levering action is usually bypassed by pulling upward on the laryngoscope handle to lift the tongue out of the visual axis. In practice, the action of displacing the tongue is also limited by the size of the mouth opening and is insufficient for sweeping aside the tongue mass, particularly in view of the distance of the tongue mass from the mouth opening. Because the laryngoscope blade is necessarily formed of a hard, inflexible material, and the manipulation awkward and challenging, dental damage is a potential result when significant pressure is exerted, which all too often is a risk when performing laryngoscopy. This is certainly accentuated in patients with difficult and narrow airways, due their neck length, body habitus, pharyngeal space opening, tongue size and other pertinent variances.
Some conventional laryngoscopes attempt to improve the practitioner's view during insertion by providing a lighted video scope or fiber optic viewing device. The video scope is carried by the laryngoscope with the objective lens located at a distal end and arranged so that the user may, via a proximal viewing end of the video scope, observe the advancement of the laryngoscope and the endotracheal tube. A camera may also be mounted in the vicinity of the distal end of the laryngoscope blade and a viewer mounted to the laryngoscope, such that the practitioner has a simultaneous line of sight and camera view during insertion. Such laryngoscopes provide for observable advance of the leading end of an endotracheal tube through the glottis and into the larynx adjacent to the vocal cords.
For the foregoing reasons, there is a need for a new laryngoscope blade for better manipulation from outside the oral cavity and for sufficiently deflecting the tongue muscle away from the glottis opening for exposing and visualizing the larynx and the vocal cords.